How does Simparica work against fleas? - briefly
Simparica contains sarolaner, an oral acaricide that binds to GABA‑ and glutamate‑gated chloride channels in flea nervous systems, causing rapid paralysis and death. A single dose provides continuous protection for up to 35 days, eliminating existing infestations and preventing new ones.
How does Simparica work against fleas? - in detail
Simparica contains sarolaner, an isoxazoline compound that targets the nervous system of fleas. After oral administration, the drug is absorbed rapidly into the bloodstream, reaching peak plasma concentrations within a few hours. The circulating sarolaner is ingested by feeding fleas, where it binds to GABA‑gated and glutamate‑gated chloride channels in the parasite’s nerve cells. This binding blocks inhibitory neurotransmission, producing uncontrolled neuronal firing that results in rapid paralysis and death of the insect.
The systemic nature of the medication eliminates the need for external contact with the flea. Because the active ingredient is present in the host’s blood for approximately 30 days, any flea that bites the animal during this period is exposed to a lethal dose. Efficacy studies show adult flea mortality occurring within eight hours of exposure, with a subsequent reduction in egg production and interruption of the flea life cycle. The prolonged half‑life of roughly 12 days sustains therapeutic concentrations, providing month‑long protection against re‑infestation.
Key pharmacological attributes include:
- Selective affinity for arthropod chloride channels, minimizing interaction with mammalian receptors.
- High oral bioavailability, allowing consistent plasma levels from a single dose of 2 mg/kg.
- Rapid onset of action, achieving > 95 % flea kill within 8 hours after treatment.
- Sustained efficacy throughout the dosing interval, preventing development of immature stages.
Safety data indicate a low incidence of adverse reactions, primarily mild gastrointestinal signs. The mechanism relies on a molecular target absent in mammals, which underpins the favorable safety profile. Proper dosing according to body weight ensures that therapeutic concentrations are achieved without exceeding the safety margin.
Overall, the combination of rapid absorption, selective neurotoxic action, and prolonged systemic presence enables Simparica to control flea infestations effectively with a single monthly oral dose.